One part of this voltage with short continuance and small harm is a self-induced electromotive force produced by a sudden changing lord current.

其一为定子绕组中负载电流突变产生的自感电动势，其特点是持续时间短，危害较小；

Firstly, the relationship between the induced electromotive force (EMF) and the terminal voltage under different operation conditions is worked out with the phasor graph of the induction motor.

首先根据感应电动机的相量图，求出了在不同工况下感应电势与端电压之间的关系。